“…Regarding the molecular orbital method, the state of an electron in a multi-electronic system is described by a one-electron wave function, called the molecular orbital. Since most of the properties of a multi-electron system are related to valence electrons motion, molecular orbitals are commonly searched in the form of linear combinations of valence atomic orbitals of atoms in the system (Downton and Wang, 2006;Shi et al, 2014;Tang et al, 2016;Huang et al, 2018). Exponential type Gauss or Slater functions are used as atomic orbitals.…”